feature Choosing A Limiter Pro Tools Limiter Shootout: Part 2

Mike Thornton We follow up our comprehensive round-up of mastering limiter plug-ins for Pro Tools with a look at ince we published our shootout of mastering limiters for Pro Tools in the hot new products from three further manufacturers. S May 2006 issue, PT users have seen two new mastering limiter plug-ins released except that it has a graph section added into meters always upsample to make sure from TC Electronic and Massey Labs. We’ve the window. This shows a very inter-sample peaks are detected and also had several letters pointing out that the comprehensive dither and noise-shaping measured — the meter scale goes beyond original roundup didn’t include Wave Arts’ section with a good selection of 0dBFS to +3dBFS so you know you are popular Final Plug or Multi Dynamics, so in noise-shaping curves to suit the different going right over. TC Electronic boast that this month’s Pro Tools workshop, we’re sample rates and bit depths. It has a feature Brickwall Limiter is bit-transparent below going to run a ‘take two’ shootout where you can turn off the dither noise with its threshold, and there is a green light next comparing all these limiters. In the interests a Mute button, allowing you to compare the to the Threshold control which lights to of fair play all round, I’ll be using the same undithered sound with the dithered output. show when it is operating in bit-transparent comparison procedure and the same test Final Plug also includes a range of presets mode. However, Brickwall Limiter only has source material; for more details see May’s ready for CD and DVD Audio mastering. basic bit-depth management and dither, issue, or read the article on-line at Unlike the other products on test here, with no noise-shaping options available. www.soundonsound.com/sos/may06/ Wave Arts’ plug-ins are not available in • Massey L2007 articles/ptworkshop_0506.htm. TDM format, but they are the only ones of This new limiter comes from Stephen the three that include Audiosuite off-line Massey, who used to work for Trillium Lane Single-band Contenders versions. Labs and has now set himself up producing TC’s MD3 Stereo Mastering package includes • TC Electronic Brickwall Limiter very cost-effective plug-ins that are creating a single-band and multi-band limiters, while TC’s Brickwall Limiter and MD3 were lot of interest. Stephen’s L2007 mastering Wave Arts’ Final Plug and Massey Labs’ originally options for the System 6000 limiter looks excellent value — you get both L2007 are single-band designs, so there are hardware processor, and software versions TDM and RTAS versions for $89 — and is three new entrants in this category. have been around for quite a while as part again similar in look to the Waves L-series, • Wave Arts Final Plug of the Powercore mastering suite, but TC except that he has chosen to go for knobs to Final Plug is a look-ahead peak limiter have only just got around to releasing Pro adjust the threshold and output level. In with bit-depth management and Tools versions of them. Brickwall Limiter addition there are two rotary switches, the noise-shaping dithering. It looks and feels operates at 48-bit and uses a five-times first of which is called Mode and alters the very simple to the Waves L1/L2/L3 range oversampling algorithm for accuracy. The behaviour of the envelope detector, packaging a complex range of adjustments into a simple four-position control. The Release rotary switch is obvious in its function and settings. Multi-band Contenders In the multi-band category we have TC Electronic’s MD3 and the Wave Arts Multi Dynamics plug-in. • TC Electronic MD3 The MD3 plug-in is much more than a multi-band limiter: it has an EQ section with four-band parametric EQ, a normaliser section, a three-band dynamics section with compressor, limiter and expander options, an M&S encode and decode option and a brickwall limiter on the end. Other interesting features include automatic gain make-up and a lookahead to help with peak handling. All of this makes MD3 a very comprehensive mastering tool in one package.

220 www.soundonsound.com • august 2006 The main window has six pages, which relate to MD3’s various sections. It starts Loudness Improvements: Single-band Limiters with the main page, where you set input Loudness Leq Drum & bass Rock opera Jazz quartet Classical Vocal ballad levels, M&S encoder and decoder options, L1 6.1 7.9 7.0 4.3 4.6 and the crossover points between the three L2 7.4 9.6 7.6 4.9 6.9 dynamic bands. Next we have a page for the L3 Ultramaximiser 8.5 9.4 8.5 6.6 7.0 Maxim 6.2 9.4 6.2 3.7 5.5 four-band EQ section, followed by a Oxford Limiter 6.3 8.1 8.0 5.8 6.7 Normalise page to help adjust the levels Ozone Loudness Maximiser 6.7 9.9 10 5.7 7.8 going into the dynamics section. This takes Brickwall Limiter 6.8 8.4 8.3 6.3 6.7 up the next two pages, one for an expander Final Plug 6.5 8.3 9.1 6.4 5.2 page and the next for a compressor. Finally, L2007 8.3 8.5 8.8 6.5 7.0 the output page includes the brickwall limiter. • Wave Arts Multi Dynamics Sound Quality: Single-band Limiters The Multi Dynamics plug-in offers up to Drum & bass Rock opera Jazz quartet Classical Vocal ballad six bands of dynamics with both L1 6 (out of 10) 7 5 6 7 compression and expansion, and has a L2 8 7.5 6 6.5 7.5 comprehensive graphical interface to display L3 Ultramaximiser 9 8 7.5 8 9 everything that is going on in just one Maxim 6 7.5 7 8 8 plug-in window. Oxford Limiter 8 8.5 8 9 8.5 Ozone Loudness Maximiser 8 8.5 9 8.5 8.5 Unlike conventional dynamics processors Brickwall Limiter 8 8.5 8.5 8 8 that work around threshold, ratio and gain Final Plug 8 8 7 8.5 7.5 make-up controls, Multi Dynamics still has L2007 8.5 8.5 8 9 8.5 threshold and ratio controls but the gain make-up is replaced by two separate controls. Simply put, the Lo Gain control more attenuation the lower the signal goes and choir, a jazz quartet piece, a solo vocal determines the amount of gain applied to below the threshold, but in Multi Dynamics ballad and a classical orchestra piece. First the signal when it is below the threshold, the maximum attenuation is set by the Lo I measured the loudness (Leq A-weighted) of and the Hi Gain control determines the Gain control. To configure Multi Dynamics the unmastered version of each track to get amount of gain applied above the threshold. as a compressor, therefore, you set the Lo a reference. Then I used each limiter to The steepness of the transition from Lo Gain Gain higher than the Hi Gain, while if it is an increase the loudness as far as I could to Hi Gain, as the signal passes through the expander you need, you set the Lo Gain without experiencing unacceptable threshold, is set by the ratio control. So below the Hi Gain. side-effects. Finally, I measured the loudness unlike a conventional compressor that of the processed version and came up with a continues to apply more gain the further The Tests loudness improvement score for each track past the threshold the signal goes, Multi Just to recap from May’s article, my tests processed by each limiter. The loudness Dynamics limits the maximum amount of used five clips covering a wide range of increase is a definite measurement, and gain with the Hi Gain control. Similarly, a different programme material: a drum although I acknowledge that the point where conventional expander continues to apply & bass track, a rock opera with solo vocal unacceptable side-effects start is subjective, the fact I did all the tests during the same session, then reviewed the results and redid any that I wasn’t happy with, should give as fair a test as I could achieve. See the test results table for more information. On this take 2 shootout I used the best two in each category to get a sensible benchmark to compare sound quality. Single-band Limiters • Drum & bass The three new limiters were all quite similar to each other, but L2007 edges it for me, maintaining some space whilst producing very high gain improvements. • Rock opera Again, all three were very similar in sound, although Final Plug appeared to produce some strange intermodulation-type effects which only became obvious while I was doing the final comparisons between each version of this track. However, they all managed to retain the vocal cut I commented on in the original article. • Jazz quartet

august 2006 • www.soundonsound.com 221 feature pro tools

MASTERING LIMITER SHOOTOUT The problem with the piano under the vibes distorting showed up again with all Loudness Improvements: Multi-band Limiters three contenders. Final Plug suffered the Loudness Leq Drum & bass Rock opera Jazz quartet Classical Vocal ballad most with TC’s Brickwall Limiter performing Ozone Multi-band Dynamics 1.1* 4.3 4.5 2.0 3.4 the best. T-Racks Multi-band Master Limiter 8.4 9.8 7.3 5.2 5.7 • Classical L3 Multimaximiser 8.6 9.5 8.7 6.7 7.4 MD3 9.5 10.3 10.1 6.7 9.5 All three handled this remarkably well. Multi Dynamics & Final Plug 8.1 8.3 9.8 6.5 7.6 Brickwall Limiter produced a less smooth, rounded sound and yet again L2007 handled *Note that Ozone’s Multi-band Dynamics module is not primarily intended for loudness maximisation. itself very well, especially with the Mode switch on Mellow. • Vocal ballad Sound Quality: Multi-band Limiters This track proved just as hard for the Drum & bass Rock opera Jazz quartet Classical Vocal ballad three new contenders as for the products in Ozone Multi-band Dynamics 5 (out of 10) 6 6.5 6 6.5 the first round-up. I had to reduce the T-Racks Multi-band Master Limiter 9.5 9 8.5 8 9 amount of limiting significantly on Final Plug L3 Multimaximiser 9 9.5 9.5 8.5 9.5 to lose the problem of hearing it work too MD3 10 10 10 9.5 10 hard. Brickwall Limiter did remarkably well, Multi Dynamics & Final Plug 8 8.5 8 8 8 but the star of the show here is L2007. With the Mode switch on Smooth, it produced an excellent sound with a very good loudness Brickwall Limiter’s interface somewhat mouse. That said, let’s hope that Stephen improvement. confusing! I would have been less confused Massey continues producing plug-ins of this if the Threshold control had been called quality at an unbeatable price and that he Conclusions: Single-band Output and the Gain control Threshold, and doesn’t get swallowed up by above Limiters it took me a little while to work out what manufacturer who then immediately puts • Wave Arts Final Plug they did in practice. The bit-depth the prices up! The interface is very intuitive, and I like management and dither are hidden away on the way the meters work too. You can see another page in the plug-in window, and Conclusions: Multi-band exactly what is going on and the sound from there are no noise-shaping options, which Limiters it is good too. It is a shame that the surprises me for a plug-in in this price • TC Electronic MD3 noise-shaping profile name is truncated; you bracket. As you will see from the results tables, need to click on it to get the pull-down • Massey L2007 menu list to see the name of the profile you This plug-in has got to are using. The manual gives a very useful be the star of the show; guide as to what each profile does, when you consider its comparing where relevant to equivalent price, it is truly amazing. Waves L1 and L2 profiles. This is the only The Mode switch is simple plug-in of the three which has an Audiosuite and effective, though version, but I did come across a bug in I would have preferred to regard to this: when copying the settings have been able to go back from the RTAS version to the Audiosuite one position instead of one, the Dither profiles didn’t copy across. having to keep clicking to All the other settings came across fine, but get it back round again. the Dither profiles didn’t get transferred, I also took a little while to whether I copied and pasted the settings or find the best way of Saved them in one and opened them in the moving the mouse to get other. the rotary controls to • TC Electronic Brickwall Limiter respond accurately — as Perhaps because it’s the only one that I have said before, I doesn’t look like a Waves plug-in, I found struggle with rotary controls when using a there is no contests when it comes to multi-band limiters: TC Electronic’s MD3 walked away with it every time. At first I didn’t get on with the multi-page format of this plug-in, but very soon I found I was very easily switching between the different pages to make the various adjustments, though I do still feel they could more attempts to make this plug-in’s interface more graphical in style. Once you start to work with MD3 you find that it is perfectly designed for mastering. I especially liked the M&S feature, and was able to use it to improve the stereo presentation of all of the test tracks. I also

222 www.soundonsound.com • august 2006 feature pro tools

MASTERING LIMITER SHOOTOUT really appreciated the summary section of the window across the bottom, which What Is Dither? changes to show settings for the features Pro Tools HD systems process all audio internally do it for you. Remember that the inserts in the you select, with individual bands and global at 24-bit, and Pro Tools LE processes audio at Pro Tools master fader channel are after the controls all available at your fingertips. One 32-bit floating. Assuming we are mastering to CD, master fader itself so that last insert is the last of the other carefully thought-out features is we need to have the end result as a 16-bit file, but point in the mixer. The standard Pro Tools mixers simply truncating 24-bit audio to 16 bits produces do not add dither, so you must use a plug-in to do the provision of indicators for soft clipping what is called quantisation noise. On its own, this this for you, although Digidesign do have versions from the Normaliser section displayed in the doesn’t sound too pleasant, albeit at low level. of their HD mixers with dither built in — one for Compressor section, so you are immediately The solution to this problem might seem strange: stereo and one for surround — and you can swap aware that the preceding section is clipping we add small and controlled amounts of noise, in a to these if you wish. without having to even select it to check. In process called dithering. Amazingly, adding a The term ‘noise shaping’ refers to the fact that general I found it very easy to get a good small amount of noise actually increases the dither algorithms can be designed to concentrate sound with this plug-in. TC Electronic have low-level detail in a digital audio signal. the noise energy in areas where the ear is less When adding dither into your final mix, you sensitive, thus making it less perceptible, got the balance of the number of controls need to make sure you only do it once, and it has although it will still work its magic by allowing available to tweak just right and the to be the last stage in the mastering process. the low level detail to come through. For pedigree from the System 6000 comes Consequently, you need to know whether your example, if your final output file is at 96kHz, you shining through in this plug-in. host application is already adding dither, and if can use a dither shape which concentrates the • Wave Arts Multi Dynamics not, you need to add a plug-in in the final stage to noise above 20kHz where we can’t hear it. Once you appreciate what this plug-in is designed to do and the function of the Lo and Hi Gain controls, its interface makes plug-in rather than a limiter per se, and the though, I still found it tricky to get a really much more sense. Wave Arts have managed same should be said for Wave Arts Multi good sound in the time available. The to get a lot of information into the one Dynamics plug-in. It is very clear in the low-level content came across as gritty, window, and designed an intuitive graphical manual that it is designed to perform as a which is why it got marked down on sound interface. I like the ‘roller’ controls that dynamic EQ processor. This doesn’t rule it quality. It may well be possible with more time and experience with this plug-in to get a better result, but at the end of the day I didn’t get on with it particularly well as a mastering tool. Overall Comments In the single-band section the overall winner has to be the Massey L2007 mastering limiter. It performed very well on both loudness improvement and sound quality, and at the price, it is just amazing. In the multi-band section, TC’s MD3 is top of the list, not just among these three products but of all the multi-band limiters I’ve tried. The sound quality was always just that bit smoother and rounder than the competition. It isn’t the cheapest plug-in, but if you are serious about mastering it is well worth the money.

Contact Details Wave Arts £ Final Plug and Multi Dynamics $199.95 each. T Wave Arts +1 781 646 3794. F +1 781 646 7190. W www.wavearts.com

TC Electronic control a parameter across all bands, and out it as a mastering tool — far from it, it is £ MD3 Stereo Mastering (includes MD3 and the way the cursor changes to an up/down very useful at handling all sorts of problems Brickwall Limiter) £1116.25 including VAT. indicator when you adjust a control to show that neither EQ nor dynamics plug-ins will T TC Electronic +44 (0)800 917 6510. you which way to move the mouse. It is handle by themselves. As MD3 has a limiter F +44 (0)800 917 6510. [email protected] features like this that, for me, make such a in its final stage, it seemed a fairer E W www.tcelectronic.com big difference in the ease of use of any comparison to put Wave Arts Final Plug after plug-in or application. Multi Dynamics and set them up together, Massey Labs In the first shootout, we had the Izotope so Multi Dynamics’ scores in the multi-band £ L2007 $89. Ozone multi-dynamics section, which turned section are for both plug-ins together. W www.masseyplugins.com out to be much more of a dynamic EQ Even with the two plug-ins in tandem,

224 www.soundonsound.com • august 2006